Field of the Invention
The present invention relates to a cable tie (clamping band) for clamping or binding a clamped article (e.g., a wiring harness that is used for vehicle wiring).
Description of Related Art
A known cable tie is taught by, for example, Japanese Patent No. 5478374. The known cable tie is a one piece plastic molded article that is integrally formed using a molding die. The cable tie includes a desired length of flexible belt (holding member) that is configured to hold a clamped article (e.g., a wiring harness), and a buckle integrally connected to one longitudinal end of the belt. The belt has a plurality of teeth or rack teeth that are formed in a surface thereof and are arranged in series in a longitudinal direction. Conversely, the buckle has a through hole into which the belt is inserted. Further, the buckle has an engagement strip (buckle tongue) formed in the through hole. The engagement strip has a plurality of engagement claws formed in a distal end thereof and is configured to bend or flex about a proximal end thereof. The engagement claws are arranged and constructed to engage the rack teeth formed in the belt when the belt is inserted into the through hole of the buckle.
In order to clamp the clamped article, the belt is wrapped around the clamped article. Thereafter, a free end (the other longitudinal end) of the belt wrapped around the clamped article is inserted into the through hole of the buckle and is then drawn from the buckle. Subsequently, the belt is tightened by pulling the free end thereof. At this time, the engagement claws formed in the engagement strip of the buckle can automatically engage the rack teeth of the belt, so that the belt can be locked or secured to the buckle. Thus, the clamped article can be clamped by the cable tie.
Generally, in a fastened condition in which the belt wrapped around the clamped article and inserted into the through hole of the buckle is fastened, a belt extraction load may sometimes be applied to the belt in a belt extraction direction opposite to a belt insertion direction. However, the belt extraction load can be received by engagement surfaces of the engagement claws via tooth surfaces of the rack teeth of the belt, so that the engagement claws may be prevented from being disengaged from the rack teeth of the belt. Thus, the belt may be prevented from being unexpectedly withdrawn or extracted from the through hole of the buckle. Further, when the belt extraction load is applied to the belt, the engagement claws of the engagement strip can be pulled in the belt extraction direction by the rack teeth of the belt while the engagement strip can be flexed toward the belt. As a result, the engagement surfaces of the engagement claws can be inclined with respect to the tooth surfaces of the rack teeth of the belt in the belt extraction direction such that the belt extraction load can be deflected from the belt extraction direction. Therefore, when a large belt extraction load greater than a predetermined value is applied to the belt in the fastened condition, the engagement surfaces of the engagement claws may be excessively inclined with respect to the tooth surfaces of the rack teeth of the belt. As a result, the large belt extraction load cannot be effectively absorbed or received by the engagement claws, so that the engagement claws may be disengaged from the rack teeth of the belt. This means that the belt may be unexpectedly withdrawn or extracted from the through hole of the buckle.
Therefore, in order to prevent the engagement claws from being disengaged from the rack teeth of the belt (i.e., in order to prevent the belt from being withdrawn or extracted from the through hole of the buckle) even when the large belt extraction load is applied to the belt in the fastened condition, the engagement surfaces of the engagement claws (and/or the tooth surfaces of the rack teeth) may be previously angled in the belt insertion direction (i.e., a direction opposite to the belt extraction direction) so as to withstand the large belt extraction load applied to the belt. According to the structure, when the large belt extraction load is applied to the belt, the engagement surfaces of the engagement claws can be prevented from being excessively inclined with respect to the tooth surfaces of the rack teeth of the belt. Therefore, the engagement claws can be effectively prevented from being disengaged from the rack teeth of the belt even when the large belt extraction load is applied to the belt. As a result, the belt may be prevented from being unexpectedly withdrawn or extracted from the through hole of the buckle.
However, in order to angle the engagement surfaces of the engagement claws (and/or the tooth surfaces of the rack teeth) in the belt insertion direction, the molding die used to manufacture the cable tie must be specially designed or redesigned with a draft angle and/or an undercut shape. Thus, there is a need in the art for improved cable ties.